Stitch cam structure



United States Patent Ofitice 3,192,742 Patented July 6, 1965 3,192,742 STITCH CAM STRUCTURE Salomao J. Haddad, Charlotte, N.C., assignor to Caroiinn Knitting Machine Corporation, a corporation of North Carolina Filed May 8, 1962, Ser. No. 193,234 Claims. (Cl. 66-57) The present invention relates to the production of circular knit fabric, and more particularly to an improved method and means for knitting in a manner that allows both the yarn and the knitting machine elements to tolerate substantially increased operating speeds While not affecting the quality of the knitted fabric.

Heretofore the speeds at which knitting machines could operate satisfactorily have been restricted by the limitations of the yarn and machine elements to withstand the sudden tension and strain developed during loop drawing, which imparts sufficient tension to the yarn to pull enough yarn into the loop to form a loop of proper size, and is performed sharply to draw loops one at a time and avoid the additional severe yarn strains that would occur if more than one loop were attempting to pull yam from the supply at the same time. This sharp drawing under tension not only strains the yarn, but also imparts sudden impact strains on the knitting needles and other machine elements in performing the sharp drawing operation. As these strains increase with increased knitting speed there are definite practical limitations on the speed at which these machines can operate satisfactorily to knit an acceptable fabric.

By the present invention this sharp drawing under tension is substantially eliminated by a gradual drawing of loops loosely so that the needles and other machine elements are manipulated gradually and the yarn, being loose, is not under substantial tension, thereby allowing the machine and yarn to withstand substantially increased knitting speeds.

This gradual and loose drawing of the present invention is accomplished by first forming measured loops in advance of drawing so that the yarn necessary to draw each loop is available without requiring a drawing tension sulficient to pull additional yarn from the yarn supply as is necessary when loops are drawn directly without prior measuring. The loops are then drawn loosely, as by limiting the depth of draw and are not subjected to the tensions inherent in conventional sharp direct drawing. Also as suificient yarn is appropriated for each loop prior to drawing and there is no appreciable drawing of additional yarn into each loop, the drawing can be accomplished gradually without limitation to drawing one loop at a time. Thus the needles can be manipulated gradually without the strain inherent in sharp drawing.

The measuring of loops prior to drawing, which is combined in the present invention with gradual and loose drawing to permit substantially increased knitting speeds, is disclosed and claimed in my copending US. patent application Serial No. 71,503, filed November 25, 1960, now US. Patent No. 3,054,278.

In addition to the above described gradual and loose drawing, the present invention provides for the combination of this feature with the alternative of knitting with a sharp direct draw. Thus portions of a fabric may be knit at high speeds utilizing the above gradual and loose draw while other portions may be alternatively knit with a sharp direct draw at conventional speeds where desired or necessary.

In one embodiment of the present invention the foregoing gradual and loose drawing is accomplished by means of a stitch cam having a loop measuring surface that manipulates needles to form measured loops, followed by a loop holding surface for maintaining needles to retain a plurality of measured loops in advance of drawing, which facilitates the establishment of measured loops and separates the drawing from the tension of the yarn supply, and a loop drawing surface that is gradually inclined and is limited in depth of draw so as not to tension the yarn and to provide gradual manipulation of the needles, all so that the yarn and needles can tolerate substantially increased knitting speeds.

To provide for the aforementioned alternative knitting by drawing sharply, a retractable cam is provided in advance of the main cam for movement from an inoperative retracted position to an operative position. This retractable cam has a sharply inclined loop drawing surface for directly drawing loops one at a time and extends to a greater drawing depth than the main cam in order to pull sufficient yarn directly to form loops of proper size.

This alternative direct drawing can also be accomplished by forming the main cam in two cmponents, the leading of which is shiftable from a normal loop measuring position to a direct drawing position. The present invention is applicable to the production of knitted fabrics of various types, such as hosiery, sweaters and other textile products knit on various types and sizes of knitting machines. In knitting hosiery speeds of double or more the speeds capable with conventional direct sharp drawing have been obtained by using the gradual and loose drawing of the present invention.

The alleviation of tension during drawing provided by the present invention is also significant in the knitting of paper yarns, which, due to the physical characteristics of paper, are more susceptible to breakage under the usual tensions and contortions of loop drawing than other types of yarn.

Other and further features and advantages of the present invention will be apparent from the following description and accompanying drawings, in which:

FIG. 1 is a sectional detail of a main stitch cam embodying the present invention, shown in relation to landing cams and needles during manipulation of the needles to draw loops in accordance with the present invention, and showing in dot-dash lines the relative advanced position of a retractable stitch cam that is retracted during the operation illustrated in FIG. 1;

FIG. 2 is a view similar to FIG. 1 showing the retractable cam advanced into operating position with the needles being manipulated thereby to draw loops sharply and directly without prior measuring;

FIG. 3 is a View similar to FIG. 1 illustrating a composite stitch cam of an alternate embodiment of the present invention arranged for measuring loops and drawing loops gradually and loosely; and

FIG. 4 is a view similar to FIG. 3 showing the composite stitch cam in position for drawing loops sharply and directly without prior measuring.

In the embodiments illustrated, the present invention is shown and described as incorporated in a conventional circular knitting machine with the stitch cam construction and loop drawing manipulation modified in accord ance with the present invention. For clarity and brevity of disclosure the details of construction of the conventional knitting machine in which the present invention is incorporated are not shown or described herein, reference being made to US. Patent No. 1,282,958, issued October 29, 1918, to R. W. Scott, which shows a typical conventional circular knitting machine. Reference is also made to my above mentioned copending application Serial No. 71,503, which illustrates and describes in detail the stitch measuring aspect that is combined in the present invention with gradual and loose drawing to produce the advantageous results of the present invention.

Referring now to the drawings and first to FIG. 1, a stitch cam 10 embodying the present invention is shown manipulating needles 12 through a loop drawing cycle to perform a knitting operation in accordance with the present invention. As the needles 12 move from left to right in FIG. 1 the needle butts 14 engage the con-- toured surface 16 of the stitch camand-are guided thereby through the knitting cycle with landing cams 18, 20 and 22 limiting the downward movement of the needles 12.

The stitch cam 10 has an initial needle engaging surface 24 inclined downwardly in a gradual concave contour for initial engagement of needle butts 14 to begin the lowering of needles gently so as to minimize the impact of the needles against the cam 10. As the needles are guided downwardly along this initial needle engaging surface 24, yarn is fed into tie open hooks (not shown) of the needles.

Extending from the bottom of the initial needle engaging surface 24 is a latch closing surface 26 having a very gradual downward inclination. As the needles 12 are guided along this latch closing surface 26 the latches (not shown) are closed by the previously drawn loops carried by the needles. The gradualness of this surface 26 minimizes the strain on the needle latches at they are being closed, thereby permitting operation at higher speed without damage to the latches, needle hooks and loops.

Extending as a general concave extension of the latch closing surface 26 is a yarn measuring surface 28, which guides the needles 12 downwardly as the needles form loops in the yarn in conjunction with sinkers or Web holders (not shown). This yarn measuring surface ex tends to a low point 29 determined by the size loop to be drawn, but less than deep enough to draw loops and cast-off the loops of the previous course held on the needles.

A needle retaining surface 3t) extends from this low point 29 of the yarn measuring surface 28 and has an initial fiat portion 32 that holds the needles 12 in loop measuring position to retain, in conjunction with the sinkers or web holders, a plurality of measured loops prior to drawing. This needle retaining surface 30 extends for a space equivalent to about six needles in the embodiment illustrated and has a concave relief, portion 34 which permits slight upward movement of the needles when the cylinder is raised, thereby alleviating any sudden strain. on the loops of yarn as a result of changes in the cylinder level. Normally, except at the instant the cylinder is raised, this concave relief portion 34 is ineffectual and the needles 12 pass straight across without following the concave contour.

Following the needle retaining surface 30 is the loop drawing surface 36, extending gradually downward to draw measured loops as the previously knit course is cast-off of the needles. As the needles pass from the needle retaining surface 30 to the loop drawing surface 36 the sinkers or web holders are withdrawn in a manner disclosed in my aforementioned copending application Serial No. 71,503, to release the loops. As a result the loops are loose as they are drawn downwardly by the needles following the loop drawing surface 36. This looseness of the loops and the gradual drawing relieves the strain on the yarn during drawing so that the yarn can tolerate substantially increased operating speeds. The inclination of the loop drawing surface 36 is substantially more gradual than the loop drawing surface of a conventional stitch cam, which is sufficiently sharp to cause loops to be drawn one at a time and this gradualness results in a comparatively gentle needle manipulation such that the needles can be manipulated at substantially at the same time, notwithstanding the fact that the amount of overall downward movement effected by the loop drawing surface 36 is relatively small.

The lowermost extent 33 of the loop drawing surface 36 is at a limited depth as compared with a conventional drawing surface so that the loops drawn by the needles 12 remain in loose condition and are not subjected to a drawing tension similar to a conventional operation where the needle must pull the yarn to a sufficient depth to draw enough yarn through the preceding loop to form a new loop of proper size, which deep tensioned draw develops considerable tension in the yarn and restricts the speed at which the machine can operate satisfactorily without damaging the yarn.

Extending from the lowermost extent 38 of the loop drawing surface 36 is a flat stitch holding surface 40 that extends for a distance of about two or three needle spaces to hold the drawn stitches in place in conjunction with a lower level of the sinkers or web holders, as disclosed in afore-mentioned application Serial No. 71,503, which prevents substantial shifting of the yarn in the loops from one loop to another, thereby maintaining the loops at a uniform stitch size and stabilizing the fabric construction to provide a uniform fabric.

Finally, the stitch cam 10 is formed with an upwardly inclined relief surface 42 to permit the needles 12 to rise slightly and free the drawn loops from the position maintained by the stitch holding surface 40 as the fabric is taken up by a conventional take-up mechanism (not shown).

The landing cams 18, 20 and 22 serve the conventional purpose of limiting downward movement of the needles 12 as the needle butts 14 follow the surface '16 of the stitch cam 10. Thus the intermediate landing cam 20 has a flat surface 44 that limits downward movement of the needle butts 14 so that they will remain in the loop measuring position determined by the corresponding surface 28 of the stitch cam 10. The subsequent landing cam 22 has a fiat surface 46 to control the needles in conformance with the stitch holding surface 40 of the stitch cam 10 and has an upwardly relieved surface 48 that causes the needles 12 to rise and follow the relief surface .42 of the stitch cam 10 for release of the stitches fromthe stitch holding position.

When using the above described stitch cam 16 in a conventional knitting machine, the needles are in an initially raised position as they approach the stitch cam 10 in the direction of the arrow in FIG. 1. The needle butts 14 first engage the surface 16 of the stitch cam at the needle lowering surface 24, which gently directs the needles downwardly as yarn is fed into the hooks of the needles. The needle butts then pass over the latch closing surface 26 and are gradually lowered to cause closing of the latches. The needle butts then pass over the yarn measuring surface 28 which lowers the needles to measure the yarn over sinkers or web holders to appropriate suflicient yarn to form each loop of proper size and permit subsequent loose drawing without having to draw additional yarn during drawing.

When the needle butts 14 reach the lower point 29 of the yarn measuring surface 28, the loops have been measured to a proper size while the loops of the preceding course are still retained on the needles and do not apply any tension to the measured loops. The needles are retained in the measured loop position as the needle butts 14 pass over the needle retaining surface 30, thereby maintaining a plurality, such as 3-6 or more, of measured loops in conjunction with the sinkers or web holders, which loop retention not only stabilizes the size of each loop but also separates the subsequent drawing from the tension of the yarn supply to further facilitate loose drawing.

As the needles reach the end of the needle retaining surface 30 and begin to follow the loop drawing surface 36, the sinkers or web holders are withdrawn, thereby releasing the retained measured loops so that the yarn appropriated for each loop is loose as the needle butts 14 follow the loop drawing surface 36, which is inclined sulficiently gradual to manipulate the needles gently downward to draw the loops while still loose through the loops of the preceding course, which are cast-off before the needle butts 14 reach the bottom 38 of the loop drawing surface 36. The gradual drawing accomplished by the loop drawing surface 36 not only facilitates the loose handling of the loops without disturbing the amount of yarn appropriated for each loop even though more than one loop, as for example two, may be in the drawing stage at the same time, but also is sufficiently gradual to manipulate the needles without severe impact strains even at substantially increased operating speeds.

The looseness of the loops is also maintained by the limited depth of the draw, as determined by the bottom 38 of the loop drawing surface 36, which need be deep enough only to cast-01f the loops of the preceding course without imparting a tension to the measured loops commensurate with the drawing tension of conventional sharp drawing, and thereby avoiding any tensioning sufiicient V to tend to draw yarn from a loop that is in a following stage of draw.

Following drawing, the drawn stitches are held in drawn position for a plurality of needles, as for example 2 or 3, as the needle butts 14 follow the stitch holding surface 40 so as to stabilize the size of the finished stitch. This stitch holding after drawing in combination with the measured loop retention prior to drawing isolates the loops as they are drawn to prevent shifting or borrowing of yarn from the yarn supply or from previously completed stitches, and even though there may be some incidental shifting of yarn from loop to loop during drawing the isolation of the loops during drawing results in a restriction of this shifting to the drawing stage while the stitches are stabilized at a uniform size as the needles pass over the stitch holding surface 415.

After leaving the stitch holding surface 4% the needles are moved upwardly slightly by the relieved surface .-8 of the landing cam 22 and the relief surface 42 of the stitch cam 10 to free the stitches preparatory to subsequent raising of the needles for repetition of the knitting cycle.

In some knitting operations to which the present invention is applicable, it is sometimes desirable or necessary to knit certain portions of the fabric by a sharp and direct draw similar to the operation of conventional knitting machines. For example, in knitting seamless hosiery the courses initially lmit in the make-up and in the courses of the heel and toe pockets may be preferably knit with a sharp and direct draw, and as these portions are normally knit at a slower speed the advantages of gradual and loose draw provided by the present invention are not as significant as when knitting the welt, leg and foot portions.

To knit portions by sharp and direct drawing the present invention includes in the embodiment of FIGS. 1 and 2 a retractable stitch cam 59 mounted in advance of the above described main stitch cam 10. This retractable stitch cam 59 has a needle manipulating surface 52 sharply inclined downwardly at an inclination generally similar to conventional stitch cams so as to engage the needle butts 14 for lowering of the needles directly to a sharp drawing surface 54 that is suificiently inclined so that only one needle is drawn at a time and therefore only one loop is drawn at a time. This one at a time drawing is necessary for, if more than one loop is being drawn directly from the yarn supply, the leading loop will have difficulty drawing yarn through the following loop and the drawing tension may Well result in bursting of the yarn. However, this sharp drawing of loops one at a time results in substantial yarn tension and severe impact strains on the needles unless the operating speed is substantially restricted.

The manipulation of needles 12 by the retractable stitch cam 59 is illustrated in PEG. 2, which shows the retractable stitch cam in its advanced operating position with the bottom 56 of the draw surface 54 of the retractable stitch cam 5t) slightly lower than the lowermost extent 38 of the loop drawing surface 36 of the main stitch cam 10. This is necessary in order to draw sufficient yarn directly to form a loop of desired size and to avoid subsequent tensioning as the needles pass over the lower surface of the main stitch cam. As a result of this deeper drawing by the retractable stitch cam 50 the main stitch cam 16 is rendered inoperable when the retractable stitch cam 50 is in its operating position as shown in FIG. 2.

The leading landing cam 18 is positioned below the retractable stitch cam 5% to limit downward movement of the needles during this direct and sharp drawing by the retractable cam 59. 7

To raise the needles 12 after direct drawing the intermediate landing cam 20 is formed with an upwardly inclined surface 58 to guide the needles 12 upwardly and relieve the tension on the drawn stitches. The needles 12 then follow the contours of the main stitch cam 10 and landing cams 20 and 22, but as the loops have already been drawn to a greater depth than the maximum depth of the main stitch cam these subsequent needle manipulations are ineffectual.

The retractable stitch cam 56) illustrated in FIGS. 1 and 2 is movable from a retracted position out of engagement with the needles for needle manipulation by the main stitch cam 10 as illustrated in FIG. 1 to the advanced position for operable needle manipulation as illustrated in FIG. 2 by any conventional means such as a mechanical linkage, an electrical solenoid control, or any other conventional mechanism capable of moving the retractable stitch cam 5t into and out of the plane of the needle butts 14. The operating mechanism for the retractable stitch cam 56) is preferably controlled from the pattern drum or other conventional control mechanism on the knitting machine.

The use of a retractable stitch cam 50 in addition to a main stitch cam 113 permits knitting with two completely different needle manipulations with the camming surfaces of each being shaped independently of the other in any desired variation without restriction by the configuration of the other.

Another way of knitting alternatively so as to knit some courses by a gradual and loose draw and other courses by v a sharp direct draw is shown in the alternate embodiment of FIGS. 3 and 4. In this embodiment a shiftable stitch cam component 65 is combined with a fixed stitch cam component 62 to obtain substantially the same results obtained with the retractable stitch cam 50 and main stitch cam 19 of the preceding embodiment.

The shiftable stitch cam component 60 is mounted for shifting length-wise of the needles to raise and lower its needle manipulating surface 64 with respect to the needle butts 66. This needle manipulating surface 64 has an initial needle engaging surface 68, a latch closing surface 743, a yarn measuring surface 72 and a needle retaining surface 74, all shaped substantially similar to the corresponding surfaces of the main stitch cam 10 of the preceding embodiment for accomplishing the same needle manipulation and yarn forming functions when the shiftlalil sgitch cam component 60 is in the raised position of The fixed stitch cam component 62 has a relieved needle retaining surface 76, a loop drawing surface 78, a stitch holding surface 86) and a relief surface 82 similar to the corresponding surfaces 34, 36, 40 and 42 respectively of the main stitch cam 10 of the preceding embodiment for accomplishing, in conjunction with the shiftable stitch cam component 60, substantially the same gradual and loose drawin that is characteristic of the present invention.

Also, landing cams 84 and 86 are provided for controlling the downward extent of needle manipulation in 7 a manner similar to the corresponding landing cams 20 and 22 of the preceding embodiment. However, the landing cam 84 associated with the shiftable stitch cam component 60 is mounted for shifting with the shiftable stitch cam component to maintain a fixed needle manipulation relation thereto.

The shifting of the shiftable stitch cam component 60 and associated landing cam 84 with respect to the fixed stitch cam component 62 and associated landing cam 86 is controlled by a slot or gate 83 formed in the edge of the shiftable stitch cam component 60 adjacent the fixed stitch cam component 62, and a key 90 extending from the fixed stitch cam component 62 into the gate 83 with the vertical extent of the movement of the key 90 in the gate 88 being sufficient to form abutments for limiting the upper and lower positions of the shiftable stitch cam component 60 as illustrated.

In the raised position as illustrated in FIG. 3, the shiftable stitch cam component 60 manipulates the needles in a manner corresponding to that of the main stitch cam 10 of the preceding embodiment, and in the lowered position as illustrated in FIG. 4 the shiftable stitch cam component manipulates the needles to draw directly by positioning of the yarn measuring surface 72 at a depth below the depth of the loop drawing surface 78 of the fixed stitch cam component 62 and at a depth sufficient to draw loops directly at that point without prior measuring and holding of loops. Thus in this lowered position the shiftable stitch cam component 60 operates to manipulate the needles 92 in a generally conventional method somewhat similar to the needle manipulation by the retractable stitch cam 50 of the preceding embodiment. a The shiftable stitch cam component 60 and associated landing cam 84 may be manipulated by any known means, such as the mechanism disclosed in my aforementioned copending application Serial No. 71,503.

The present invention has been incorporated in a conventional Scott and Williams Model KN, single feed, 3% inch, 400 needle, 75 gauge circular knitting machine for knitting hosiery with a single end of 15 denier nylon yarn used to knit the leg portion of the stocking. Such a modified machine has been found capable of knitting at speeds greater than 400 rpm. without noticeable harm to the yarn, fabric, needles or other knitting machine elements. This is at least twice the speed capable for obtaining satisfactory results using an identical machine that has not been modified according to the present invention.

In this particular installation the initial needle engaging surface 24 lowers the needles to the latch closing surface 26, which lowers the needles about Ms" while closing the latches over a very gradual extent. The yarn measuring surface 28 lowers the needles to measure yarn to the point 29 at which the surface is inclined approximately 35 to 45. The needle retaining surface 30 retains the needles at the yarn measuring level over a space of approximately The loop drawing surface 36 lowers the needles about .03 ".045" over a space of about at an angle of approximately 30-35 to the direction of needle advancement. The stitch holding surface 40 holds the needles at the drawn position for an extent of about For drawing loops directly and sharply without prior measuring and holding of stitches, and without gradual and loose drawing, the bottom 56 of the draw surface 54 of a retractable stitch cam 5% or the corresponding position of the shiftable cam component 60 in the lower direct draw position is approximately .005"-.010" below the bottom of the draw surface 36, which difference indicates the limited depth of draw for drawing gradually and loosely according to the present invention. The drawing angle of the lower point 56 of the surface of the retractable cam is about 55.

In one shiftable component cam arrangement constructed according to FIGS. 3 and 4 the needle manipulating surfaces are dimensioned generally similar to the above dimensions for the embodiment according to FIGS. 1 and 2 with one difference being the measuring surface angle, which should be approximately 45 so that when the shiftable component 60 is in its lower position and the machine operated at conventional speed the needles will be capable of drawing satisfactory loops directly and sharply one at a time.

Although the details and dimensions of particular kniting machine modifications have been described above, it should be noted that these dimensions may be varied within the scope of the present invention, which is not limited to any particular size or gauge machine or to a particular yarn size as the problems of yarn strain and needle strain are inherent in all 'types of circular knitting machines wherein loops are drawn conventionally in a sharp and direct manner.

The present invention has been described in detail above for purposes of illustration only and is not intended to be limited by this description or otherwise except as defined in the appended claims.

I claim:

1. In a circular knitting machine, means for manipulating needles including first means for sequentially forming measured loops, second means for maintaining a plurality of such measured loops in advance of drawing, and third means for subsequently manipulating said needles in sequence to draw said measured loops gradually to allow substantially increased operating speed and to a limited depth to draw each loop sufiiciently loose to tolerate the substantially increased operating speed.

2. In a circular knitting machine, means for manipulating needles sequentially including first means for forming measured loops, second means for maintaining a plurality of such measured loops in advance of drawing, and third means for subsequently manipulating said needles in sequence to draw said measured loops gradually over a space of a plurality of needles to allow a substantially increased operating speed.

3. In a circular knitting machine, needle manipulating means including first means operable to cause the needles to form measured loops, second means for maintaining a plurality of such measured loops in advance of drawing, third means for subsequently manipulating said needles in sequence to draw said measured loops gradually to allow substantially increased operating speed and to a limited depth to draw each loop sufiiciently loose to tolerate the substantially increased operating speed, and further means operable alternatively with said first, second, and third means to cause the needles to draw loops sharply and directly without prior forming of loops.

4. In a circular knitting machine, a stitch cam having a loop measuring surface inclined with respect to the relative advancement of needles to cause the needles to form measured loops, a loop holding surface extending a plurality of needle spaces from said loop measuring surface in general direction of needle advancement and at a depth insufiicient to draw the measured loops, said loop-holding surface causing the needles to hold a plurality of measured loops in advance of drawing, and a loop drawing surface extending from said loop holding surface at a gradual inclination with respect to needle advancement and extending to a limited drawing depth to cause the needles gradually to draw the measured loops sufiiciently loose to tolerate a substantially increased knitting speed.

5. In a circular knitting machine, a stitch cam according to claim 4 characterized further in that a stitch holding surface extends from said loop drawing surface a plurality of needle spaces in the general direction of needle advancement and at substantially said limited drawing depth to retain a plurality of stitches at their drawn extent subsequent to drawing.

6. In a circular knitting machine, a stitch cam having a loop measuring surface inclined with respect to the relative advancement of the needles to cause the needles to form measured loops, a loop holding surface extending a plurality of needle spaces from said loop measuring surface in the general direction of needle advancement and at a depth insufficient to draw the measured loops, said loop-holding surface causing the needles to hold a plurality of measured loops in advance of drawing, and a loop drawing surface extending from said loop holding surface at a gradual inclination with respect to needle advancement for a plurality of needle spaces to cause the needles gradually to draw the measured loops with a pinrality of needles and associated loops being in progressive stages of drawing at the same time so that a substantially increased operating speed can be tolerated.

7. In a circular knitting machine, a composite stitch cam comprising a fixed component and a shiftab'le component, said shiftable component having a needle camsurface for drawing loops directly when said shiftabie cam is in one position and for measuring loops without drawing when the shiftaole cam is in another position, said fixed component having a loop holding surface extending from adjacent said shiftable component for holding a plurality of needles in loop measuring position as the needles pass from said shiftable component when the shiftable component is in said another position and having a loop drawing surface extending from said loop holding surface at a gradual inclination and extending to a limited drawing depth to cause the needles gradually to draw the measured loops sufiiciently loose to tolerate a substantially increased knitting speed when the knitting machine is operated with said shiftable component in said another position.

8. In a circular knitting machine, needle manipulating means comprising a main stitch cam having a loop meas uring surface inclined with respect to the relative advancemerit of needles to cause the needles to form measured loops, a loop holding surface extending a plurality of needle spaces from said loop measuring surface in the general direction of needle advancement and at a depth insufiicient to draw the measured loops, said loop-holding surface causing the needles to hold a plurality of measured loops in advance of drawing, and a loop drawing surface extending from said loop holding surface at a gradual inclination with respect to needle advancement and extending to a limited drawing depth to cause the needles gradually to draw the measured loops sulficiently loose to tolerate a substantially increased knitting speed, and a retractable stitch cam in advance of said main stitch cam and movable from an inoperative retracted position at which said needles are manipulated by said main stitch cam to an operative position at which said needles are manipulated by said retractable cam, said retractable cam having a needle camming surface sharply inclined with respect to needle advancement to cause the needles to draw loops sharply one at a time directly without prior measuring.

9. In a circular knitting machine, needle manipulating means according to claim 8 characterized further in that said needle camming surface of said retractable stitch cam extends to a greater drawing depth than said loop drawing surface of said main stitch cam.

10. In a circular knitting machine, needle manipulating means comprising a main stitch cam and a retractable stitch cam in advance of said main stitch cam movable from an inoperative retracted position for manipulation of needles by said main stitch cam to an operative position at which needles are manipulated by said retractable stitch cam, said cams having loop drawing surfaces for manipulation of needles to draw loops, the loop drawing surface of said retractable stitch cam extending to a greater drawing depth than the loop drawing surface of said main stitch cam to render the loop drawing surface of the main stitch cam inoperative when said retractable cam is in said operative position.

References Cited by the Examiner UNITED STATES PATENTS 2,179,785 11/39 Gallagher 66l69 2,228,633 1/41 Leech 66169 2,435,269 2/48 Curtis et a1. 6657 2,503,838 4/50 Page w 6657 3,108,459 10/63 Coile 6641 DONALD XV. PARKER, Primary Examiner.

RUSSELL C. MADER, Examiner. 

1. IN A CIRCULAR KNITTING MACHINE, MEANS FOR MANIPULATING NEEDLES INCLUDING FIRST MEANS FOR SEQUENTIALLY FORMING MEASURED LOOPS, SECOND MEANS FOR MAINTAINING A PLURALITY OF SUCH MEASURED LOOPS IN ADVANCE OF DRAWING, AND THIRD MEANS FOR SUBSEQUENTLY MANIPULATING SAID NEEDLES IN SEQUENCE TO DRAW SAID MEASURED LOOPS GRADUALLY TO ALLOW SUBSTANTIALLY INCREASED OPERATING SPEED AND TO LIMITED DEPTH TO DRAW EACH LOOP SUFFICIENTLY LOOSE TO TOLERATE THE SUBSTANTIALLY INCREASED OPERATING SPEED. 